Outline

Introduction: One determinant of prescribing rationality is the width of the drug spectrum employed by a physician. The range of substances must be broad enough to treat his patients’ conditions, including the less frequent ones, yet the physician should keep his focus on a manageable range of drugs The DU90 methodology has been introduced by Bergman et al. in Sweden as a measure of this aspect of prescribing quality.

Methods: For this talk about work in progress, we employ comprehensive prescription data from Germany’s largest group of statutory health care funds, covering roughly 35% of the population. Using ATC and DDD methodology, the DU90 measure is calculated for every physician individually. For grouping purposes, we are, for he first time, able to use the much cleaner specialty coding introduced in mid-2008. This provides an empirical overview of the DU90 distribution. More detailed analyses include differences in the distributions due to region and physician’s age. German results are compared to surveys from Sweden undertaken by Wettermark et al.

Results: As expected, the median DU90 value varies strongly with the doctor’s specialty, where GPs show the highest median value. Comparisons of DU90 variants based on different ATC levels show that most of the variation is due to the use of different substance classes, but neither is the contribution of intra-class drug choice negligible. Specialists exhibit much narrower spectra than GPs, but both median and inter-doctor variances depend heavily on the exact field of specialisation. Regional differences appear to be less important, but there is evidence that the doctor’s age, which may be viewed as a proxy for the duration of his professional activity, has some influence.

Discussion and conclusion: While an analysis of the factual cannot answer the normative question for the “right” value that one should aim for, it does provide a scale on which physicians can be “benchmarked”, e.g., in the context of academic detailing. This alone provides an important starting point for a wider acceptance of this measure in Germany. Comparison with Swedish results shows, however, that rational prescribing in Germany still exhibits a potential for improvement. It seems unlikely that the variation between doctors can be explained overall by differences in patients’ morbidity structure. Further research, e.g., using data about diagnoses, is needed.